Manufacturing method for waveguide

Abstract

A method of manufacturing a waveguide for a head mounted display may include joining a first set of waveguide elements using one or more adhesives that are sensitive to heat or chemical removal and joining a second set of waveguide elements using one or more adhesives that are not sensitive to heat or chemical removal to form a waveguide stack, the stack of waveguides is cut to form waveguide structures with embedded facets or diffractive elements, and portions corresponding to the first set of waveguide elements are removed using thermal or chemical removal while portions corresponding to the second set of waveguide elements remain in engagement.

Description

Technical Field

[0001] The present disclosure relates to the field of near-eye display systems such as head-mounted displays. More specifically, the present disclosure relates to a method for manufacturing a waveguide for a near-eye display (NED). Background Art

[0002] Consumer demand for improved human-machine interfaces has led to increased interest in high-quality image head-mounted displays (HMDs) or near-eye displays, commonly referred to as smart glasses. These devices can provide virtual reality (VR) experiences or augmented reality (AR) experiences, enhancing the way users interact with digital content and the environment around them.

[0003] Consumers seek better image quality, immersive experience and greater comfort when using HMDs. Consumers expect displays to have high resolution, vivid colors and minimal distortion to create a realistic and enjoyable viewing experience. Since users often wear these devices for long periods of time, comfort is also a key factor. Consumers expect lightweight, stylish designs that are less obtrusive in various scenarios and more convenient to wear. Smaller devices also provide improved portability, making these devices easier to carry and use in different environments. Therefore, there is a growing demand for higher performance but smaller and more compact HMDs.

[0004] A key element in a near-eye display system is the waveguide. A waveguide is a device that directs light from the system's image projector to the user's eye. Waveguides rely on total internal reflection along major surfaces within the device to propagate light. Improving the performance of miniaturized waveguides presents certain challenges. As the performance of waveguides increases, the waveguides and the processes used to make them become more complex. Part of this complexity arises because the very features that increase performance also increase the complexity of the waveguides. Additionally, making waveguides smaller tends to complicate their production. Smaller components are more difficult to manage and more difficult to reliably reproduce. Increased manufacturing complexity tends to result in lower yields and higher costs, which tends to reduce adoption.

[0005] Therefore, innovative waveguide fabrication processes are needed that will reduce the complexity of manufacturing while maintaining or improving performance and compactness. Summary of the invention

[0006] The present disclosure relates to a method of manufacturing a waveguide for a head mounted display. The novel method may include: bonding a first set of waveguide elements using one or more adhesives that are sensitive to heat or chemical removal, and bonding a second set of waveguide elements using one or more adhesives that are not sensitive to heat or chemical removal to form a waveguide stack, cutting the waveguide stack to form a waveguide structure with embedded facets or diffractive elements, and removing portions corresponding to the first set of waveguide elements using heat or chemical removal, while portions corresponding to the second set of waveguide elements remain bonded to form a desired waveguide.

[0007] The accompanying drawings incorporated in the specification and forming a part of the specification illustrate various example systems, methods, etc., which illustrate various example implementations of various aspects of the present invention. It will be understood that the element boundaries (e.g., boxes, groups of boxes, or other shapes) shown in the figures represent an example of boundaries. It will be understood by those of ordinary skill in the art that an element can be designed as multiple elements, or multiple elements can be designed as one element. An element shown as an internal component of another element can be implemented as an external component, and vice versa. In addition, elements may not be drawn to scale. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1A A prior art waveguide system with reflecting facets is shown.

[0009] Figure 1B A prior art waveguide system with a refractive element is shown.

[0010] Figure 1C A prior art waveguide system with reflecting facets and mirror input is shown.

[0011] Figure 1D A prior art waveguide system with a refractive element and a mirror input is shown.

[0012] Figure 2A A prior art two-dimensional waveguide system with reflecting facets is shown.

[0013] Figure 2B A prior art two-dimensional waveguide system with refractive elements is shown.

[0014] FIG. 3A to FIG. 3E A manufacturing method for a waveguide stack is shown.

[0015] Figure 4A and Figure 4B A method for manufacturing a mirror coupling segment is shown.

[0016] FIG. 5A to FIG. 5C A fabrication method for a waveguide is shown.

[0017] Figure 6 An alternative manufacturing method for the waveguide is shown.

[0018] FIG. 7A to FIG. 7G A fabrication method for a two-dimensional waveguide is shown. DETAILED DESCRIPTION

[0019] Figure 1A A prior art waveguide system 1a is shown, which includes a projector 51, a collimating lens 52, and a waveguide system 10a. The waveguide system 10a includes an incoupling prism 30, a waveguide substrate 11a having a first major surface 13 and a second major surface 14, and a partially reflective surface or facet 15 disposed in the waveguide substrate 11a. In the system 1a, the projector 51 projects light corresponding to an image, which is collimated by the lens 52 before passing through the incoupling prism 30 into the waveguide 10a. Figure 1A Light rays describing an exemplary field are shown in FIG. Collimated field light rays 40 are coupled into the waveguide 11a such that image 41a and conjugate image 41b are captured between the two major surfaces 13, 14 of the waveguide 11a by total internal reflection (TIR). Light rays 41a and 41b propagate through the waveguide 11a until they interact with one of a set of co-parallel partially reflective surfaces 15 embedded inside the waveguide substrate 11a. The embedded partially reflective surface 15 is a decoupling element that couples light rays 41a, 41b out of the waveguide 11a as light rays 42 and projects the image onto the eye 5 of the user located within a predetermined eye box.

[0020] Figure 1B A prior art alternative waveguide system 1b is shown, which includes a projector 51, a collimating lens 52, and a waveguide system 10b. The waveguide system 10b includes an incoupling prism 30, a waveguide substrate 11b having a first major surface 13 and a second major surface 14, and a diffractive element 12 disposed in the waveguide substrate 11b. In the system 1b, the projector 51 projects light corresponding to an image, which is collimated by the lens 52 before passing through the incoupling prism 30 into the waveguide 10b. Figure 1B Light rays describing an exemplary field are shown in FIG. Collimated field light rays 40 are coupled into waveguide 11b such that image 41a and conjugate image 41b are captured between the two major surfaces 13, 14 of waveguide 11b by total internal reflection (TIR). Light rays 41a and 41b propagate through waveguide 11b until they interact with a diffractive element 12 embedded inside the waveguide substrate 11b. The embedded diffractive element 12 is an outcoupling element that couples light rays 41a out of the waveguide into light rays 42 and projects the image onto the user's eye 5 located within a predetermined eye box.

[0021] like Figure 1C and Figure 1D In order to minimize the size of the underlying near-eye display, it is usually necessary to place the projector at a specific position relative to the waveguide. This can be achieved by coating the incoupling prism 33 with a reflective coating and arranging the components as shown.

[0022] Figure 1C A prior art waveguide system 1c is shown, which includes a projector 51, a collimating lens 52, and a waveguide system 10c. The waveguide system 10c includes an incoupling prism 33, a waveguide substrate 11a having a first major surface 13 and a second major surface 14, and a partially reflective surface or facet 15 disposed in the waveguide substrate 11a. In the system 1c, the projector 51 projects light corresponding to an image, which is collimated by the lens 52 before being reflected by the incoupling prism 33 into the waveguide 10c. Figure 1C Light rays describing an exemplary field are shown in FIG. Collimated field light rays 40 are coupled into the waveguide 11a such that image 41a and conjugate image 41b are captured between the two major surfaces 13, 14 of the waveguide 11a by total internal reflection (TIR). Light rays 41a and 41b propagate through the waveguide 11a until they interact with one of a set of co-parallel partially reflective surfaces 15 embedded inside the waveguide substrate 11a. The embedded partially reflective surface 15 is a decoupling element that couples light rays 41a, 41b out of the waveguide 11a as light rays 42 and projects the image onto the eye 5 of the user located within a predetermined eye box.

[0023] Figure 1D A prior art alternative waveguide system 1d is shown, which includes a projector 51, a collimating lens 52, and a waveguide system 10d. The waveguide system 10d includes an incoupling prism 33, a waveguide substrate 11b having a first major surface 13 and a second major surface 14, and a diffractive element 12 disposed in the waveguide substrate 11b. In the system 1d, the projector 51 projects light corresponding to an image, which is collimated by the lens 52 before being reflected by the incoupling prism 33 into the waveguide 10d. Figure 1D Light rays describing an exemplary field are shown in FIG. Collimated field light rays 40 are coupled into waveguide 11b such that image 41a and conjugate image 41b are captured between the two major surfaces 13, 14 of waveguide 11b by total internal reflection (TIR). Light rays 41a and 41b propagate through waveguide 11b until they interact with a diffractive element 12 embedded inside the waveguide substrate 11b. The embedded diffractive element 12 is an outcoupling element that couples light rays 41a out of the waveguide into light rays 42 and projects the image onto the user's eye 5 located within a predetermined eye box.

[0024] Figures 1A to 1DA simple case is shown in which only a single set of embedded outcoupling elements 15 is used. However, more advanced structures with multiple sets of outcoupling elements can also be used. Examples of such advanced structures are shown in FIG. Figure 2A and Figure 2B Shown in.

[0025] Figure 2A A configuration 2a is shown viewed from three different directions (xy plane, xz plane and yz plane) where two sets of co-parallel partially reflective surfaces or facets 15, 35 are used, each set being embedded in a respective waveguide substrate 21a, 31a having mutually co-parallel major surfaces. Light is coupled into the waveguide portion 21a by a prism 40 and is captured in the waveguide 21a by TIR and propagates according to light ray 50a until the light interacts with the facet 15 and is redirected in the direction 50a'. The light then propagates in the waveguide 31a by TIR until the light interacts with the facet 35 and is coupled out of the waveguide portion 31a and onto the user's eye 5.

[0026] Figure 2B Configuration 2b is shown viewed from three different directions (xy plane, xz plane and yz plane) where two sets of diffractive elements 12, 32 are used, each set embedded in a respective waveguide substrate 21b, 31b having mutually co-parallel major surfaces. Light is coupled into waveguide portion 21b by prism 40 and is captured in waveguide 21b by TIR and propagates according to light 50b until it interacts with element 12 and is redirected in direction 50b'. The light then propagates in waveguide 31b by TIR until it interacts with element 32 and is coupled out of waveguide portion 31b and onto the user's eye 5.

[0027] With reference to WO2021 / 152602 (the entire contents of which are incorporated herein by reference), a method for manufacturing structures 1a, 1b, 2a and 2b including coupling elements is described. The basic concept is based on an adhesive that is sensitive to chemical reactions or heating of the material and can therefore be easily removed without damaging the optical components to which it is bonded. The method is described below in the context of configurations with reflective elements (e.g., configurations 1c and 2a), but the method is also applicable to waveguides based on diffractive elements or a combination of reflective elements and diffractive elements.

[0028] Heating for adhesive removal involves applying heat to the adhesive bond to soften or melt the adhesive, making it easier to remove. Heating in the context of the present disclosure may involve, but is not limited to, placing the bonded structure in a heated chamber (i.e., an oven). This method is particularly useful for adhesives that have high heat sensitivity or lose their adhesive properties at elevated temperatures. Examples of adhesives susceptible to heating as a means of destroying the bond include: UV curable adhesives, e.g., Loctite 3492 and Dymax OP-24, cyanoacrylate adhesives, e.g., Loctite 401 and Permaband 910, acrylic adhesives, e.g., 3M DP810 and Loctite 315. (Note: Some acrylic adhesives may have moderate temperature resistance, but they are generally less tolerant of elevated temperatures than silicones or certain epoxies.)

[0029] In contrast, some adhesives are designed to withstand higher temperatures, making them suitable for maintaining a strong bond even when exposed to high temperatures. Examples of adhesives that are not susceptible to heating as a means of breaking the bond include: epoxy adhesives, such as EPO-TEK 301 and Araldite 2021, and silicone adhesives, such as Dow Corning 3145 RTV and Momentive TSE392-C.

[0030] Chemical etching for adhesive removal involves the use of a chemical solution to disrupt the adhesive bond, either by dissolving the adhesive or by weakening the structure of the adhesive so that it can be easily wiped or rinsed away. This process is particularly useful when mechanical removal methods, such as scraping or peeling, are impractical or may damage the bonding surfaces. The choice of chemicals used in chemical etching depends on the type of adhesive and the material of the waveguide element involved. Example chemicals that can be used for etching include: acetone (effective for many types of adhesives, especially for acrylic and some epoxy and cyanoacrylate adhesives), isopropyl alcohol (IPA) (suitable for removing less aggressive adhesives), and specialized adhesive removers (these removers are formulated to remove specific types of adhesives without damaging the underlying material). Depending on the size of the area and the type of adhesive, the chemical can be applied to the adhesive using a brush, cloth, or by immersing the object in a chemical bath. Depending on the strength of the adhesive and the chemical used, the reaction time required for the chemical to interact with the adhesive can vary from a few minutes to a few hours. These chemicals work by weakening or dissolving the molecular bonds that make up the adhesive. This process causes the adhesive to swell, soften, or break down, making it easier to remove. Once the adhesive is sufficiently broken down, it can be wiped, scraped or rinsed off the surface of the waveguide component. In some cases, gentle scrubbing may be required to remove all residue. After removing the adhesive, the surface can be rinsed to remove any remaining chemical residue. The surface is then allowed to dry.

[0031] Certain adhesives used in optical glass applications may be more susceptible to chemical etching than others, especially when removing the adhesive. Examples of adhesives susceptible to chemical etching as a means of removal include: acrylic-based adhesives (generally susceptible to solvents such as acetone or isopropyl alcohol (IPA)), such as 3M DP810 and Loctite 315; cyanoacrylate adhesives (generally removable using acetone as well), such as Loctite 401 and Permabond 910; UV-cured adhesives (certain formulations may be susceptible to specific solvents such as acetone or specialized adhesive removers), such as Loctite 3492 and Dymax OP-24; certain epoxies (some specific formulations, especially those not designed for high chemical resistance, may be softened or removed with specific solvents or chemical etchants), such as EPO-TEK 301 and Araldite 2021.

[0032] In contrast, some adhesives used in optical glass applications are generally resistant to chemical etching and are designed to provide a strong, durable bond that maintains its integrity even in the presence of solvents. Examples of adhesives that resist chemical etching include: high-performance epoxies, such as EPO-TEK 353ND and Master Bond EP30-2; silicone adhesives, such as Dow Corning 3145RTV and Momentive RTV108; modified acrylic resins, such as 3M Scotch-WeldAC77 and Loctite 3301 light-curing adhesives; specialty UV-curing adhesives, such as Norland Optical Adhesive61 and Dymax 3099.

[0033] "Chemical etching" in this article can also include water dissolution. Certain adhesives can be used in optical glass applications and are more susceptible to water dissolution than other adhesives, especially when removing the adhesive. Examples of adhesives that are susceptible to chemical etching in a water-soluble form as a means of removal include: water-soluble gums and resins, such as gum arabic and dextrin-based adhesives; polyvinyl alcohol (PVA)-based adhesives, such as Elmer's glue and binder's PVA; cellulose ethers, such as methylcellulose; specialty removable adhesives, such as 3M Removable Repositionable Tape 665 (although not a traditional adhesive in liquid form, this tape uses a water-soluble adhesive that can be used for temporary positioning of optical components); and hydroxypropyl cellulose (HPC), such as Klucel TM G.

[0034] Thus, adhesives can be used in pairs or groups. The second member of a pair or group is more easily removed than the first member of the pair or group. In this way, a stack including elements joined using a first member adhesive can remain joined, while elements joined using a second member adhesive can be removed by exposing the stack to removal conditions (e.g., chemical etching (including water dissolution), heating, etc.). As described above, adhesives can be characterized as belonging to a first group, and the adhesives in the first group are less easily removed by chemical etching or heating than corresponding adhesives in the second group that are more easily removed by chemical etching or heating.

[0035] A method of manufacturing a waveguide for a head mounted display may include: joining a first set of waveguide elements with one or more adhesives from a first group (adhesives that are not sensitive to thermal or chemical removal), and joining a second set of waveguide elements with one or more adhesives from a second group (adhesives that are sensitive to thermal or chemical removal) to form a waveguide stack. The waveguide stack may then be cut to form a waveguide structure having embedded facets or diffractive elements. Portions corresponding to the second set of waveguide elements (joined using an adhesive that is sensitive to removal) may be removed from the waveguide structure using thermal or chemical removal, leaving only the desired first set of waveguide elements.

[0036] FIG. 3A to FIG. 3E The fabrication of a waveguide stack 100 is shown.

[0037] exist Figure 3A In the embodiment, the plate 101 is treated (e.g., coated) to enable its top surface 101a or bottom surface 101b to partially reflect or diffract. Figure 3A As shown in FIG. 1 , the boards 101 are joined together at the top surface 101a or the bottom surface 101b to form a waveguide block 102. The boards 101 are joined to each other using an adhesive selected from the first group of adhesives (i.e., adhesives that are not sensitive to thermal or chemical removal). The waveguide block 102 can then be cut along a plane 103 that is at an acute angle relative to the top surface 101a and the bottom surface 101b. Figure 3B As shown in FIG. , the resulting waveguide slice 11 (similar to Figure 1C Each of the waveguide structures 11a) has a top surface 13, a bottom surface 14 and an internal facet 15. The resulting slices can also be cut along a plane perpendicular to the plane 103 to obtain Figure 3B The rectangular shape shown in .

[0038] exist FIG. 3C to FIG. 3D , block 111 and plate 112 may be bonded together using an adhesive selected from a second group of adhesives (i.e., an adhesive that is sensitive to thermal or chemical removal) to form a second block 113 having a top surface 115 and a bottom surface 116. Plate 112 may be selected to be relatively thin to minimize portions of plate 112 that may remain with the final waveguide or may need to be polished away from the final waveguide. Second block 113 may then be cut along plane 114 (e.g., parallel to top surface 115 and bottom surface 116) to form placeholder slices 117.

[0039] exist Figure 3E In the embodiment, the waveguide slices 11 and the placeholder slices 117 are alternately bonded together to form the intermediate waveguide stack 100. The waveguide slices 11 and the placeholder slices 117 are bonded using an adhesive selected from the second group (i.e., an adhesive that is sensitive to chemical etching or heating removal), and thus can be easily removed and separated from each other later.

[0040] Figure 4A and Figure 4B The fabrication of a mirror coupling section 200 is shown.

[0041] exist Figure 4A In the embodiment of the present invention, the coupling plate 201 is treated (e.g., coated) so that its top surface 201a can reflect or diffract to act like a mirror. The top (i.e., mirror) surface 201a of the coupling plate 201 can then be bonded to the first surface of the sacrificial plate 202 and the bottom surface 201b of the coupling plate 201 can be bonded to the second surface of the sacrificial plate 202 to form a coupling stack 203 having a top surface 201a and a bottom surface 201b. To allow for subsequent removal of the sacrificial plate portion, an adhesive selected from the second group of adhesives (i.e., an adhesive that is sensitive to chemical etching or thermal removal) can be used to complete one or both of the following operations: bonding the top (i.e., mirror) surface 201a of the coupling plate 201 to the first surface of the sacrificial plate 202, or bonding the bottom surface 201b of the coupling plate 201 to the second surface of the sacrificial plate 202. In another embodiment, the coupling plates 201 can be bonded to each other using an adhesive selected from the second group of adhesives (i.e., an adhesive that is sensitive to chemical etching or heat removal) to form a coupling stack 203. The coupling stack 203 can then be cut along a plane 204 that is at an acute angle relative to the top surface 201 and the bottom surface 201b. Figure 4B As shown in , the resulting coupling stack segments 200 each include a plurality of coupling planar segments that will become prisms 33.

[0042] FIG. 5A to FIG. 5C The fabrication of a waveguide 10 similar to the waveguide 10c described above is shown.

[0043] exist Figure 5A , the waveguide stack 100 is bonded to the coupling stack segment 200 to form a waveguide structure 250. Specifically, the coupling plane segment 33 in the coupling stack segment 200 is aligned and bonded to the corresponding waveguide slice 10 in the waveguide stack 100 using an adhesive selected from the first group of adhesives (i.e., an adhesive that is not sensitive to chemical etching or heating removal). The coupling plane segment 33 can also be permanently bonded to the placeholder plate portion 112 of the placeholder slice 117, but most of the placeholder material will be removed in the form of the placeholder block portion 111. The waveguide structure 250 can then be cut along a plane 253 that generally continues the bottom surface 14. As shown in FIG. Figure 5B As shown in , the plane 253 is therefore substantially parallel to the top surface 13 and the bottom surface 14 to form the waveguide structure segment 260.

[0044] exist Figure 5C, portions corresponding to the placeholder slice 117 and the sacrificial plate 202 (i.e., any portions joined using an adhesive selected from the second group of adhesives) have been removed from the segment 260 by chemical etching or heating to obtain the waveguide 10c. Any remaining undesirable material (e.g., the remaining portion of the plate 112) can be left in place, because its relatively small size will not significantly affect the performance of the resulting waveguide 10c. Alternatively, the undesirable material can be polished away, for example, during the polishing of the bottom surface 14 of the waveguide 11c. Since the size of this portion 112 is not very large compared to the entire waveguide, the major surface 14 of the waveguide 11c dominates the polishing process, and the major surface 14 will be uniform and parallel to the top major surface 13 with high precision.

[0045] Figure 6 Shows FIG. 5A to FIG. 5C An alternative embodiment of the embodiment of . Figure 6 In the arrangement of , the spacer slice 118 remains as part of the final waveguide 10d. If the spacer slice 118 is manufactured with very high precision co-parallel surfaces, the bonding between the spacer slice 118 and the waveguide 11c can be performed using an adhesive from the first group with a sufficiently low refractive index (i.e., an adhesive that is not sensitive to the removal process) so that the light can be confined (TIR) ​​within the waveguide 11c. In this case, it is not necessary to form the spacer slice 118 from two different parts 111 and 112 (such as Figure 3C d), since the spacer slices 118 remain intact in the final waveguide 10d and can therefore be made from a single part.

[0046] The novel techniques disclosed herein can also be applied to more advanced configurations, such as Fig. 7A To that shown in Figure 7J with reference to WO2023026266A1 (the entire contents of which are incorporated herein by reference).

[0047] exist Fig. 7A In the embodiment, the top surface 301a or the bottom surface 301b of the first waveguide plate 301 is treated (e.g., coated) to enable the top surface 301a or the bottom surface 301b to partially reflect or diffract. Then, the first waveguide plate 301 can be bonded at the top surface 301a or the bottom surface 301b using an adhesive selected from the first group of adhesives (i.e., an adhesive that is not sensitive to chemical etching or heating removal) to form a first waveguide block 300. Then, the first waveguide block 300 can be cut along a first plane 303 that is acutely angled with respect to the top surface 301a and the bottom surface 301b. The resulting one or more first waveguide blocks 310 have an internal facet 15. The resulting one or more waveguide blocks 310 can also be cut along a plane perpendicular to the plane 303 to obtain Figure 7B The rectangular shape shown in .

[0048] exist Figure 7C In the embodiment, the structure of the waveguide slice 11 is the same as that of the above reference Figure 3A and Figure 3B , and are bonded together using an adhesive selected from the first group of adhesives (ie, an adhesive that is not sensitive to chemical etching or thermal removal) to form a waveguide stack 500.

[0049] The top surface 41a or the bottom surface 41b of the third waveguide plate 410 may be processed to enable the top surface 410a or the bottom surface 410b to partially reflect or diffract. Figure 7C In the illustrated embodiment, the thickness of the top third waveguide plate 410 and the bottom third waveguide plate 410 is half the thickness of the third waveguide plate 410 located between the top and bottom. The top third waveguide plate 410 and the bottom third waveguide plate 410 can be prefabricated to be thinner, or more practically, as described above with reference to Fig. 7E As described, the top third waveguide plate and the bottom third waveguide plate become thinner when cut along the plane 603. Then, the third waveguide plate 410 can be bonded at the top surface 410a or the bottom surface 410b using an adhesive selected from the first group of adhesives (i.e., an adhesive that is not sensitive to chemical etching or heating removal) to form the mixer block 400.

[0050] like Fig.7D As shown in , the first waveguide block 310 can be bonded to the mixer block 400 and the mixer block 400 can be bonded to the waveguide stack 500 using an adhesive selected from the first group of adhesives (i.e., an adhesive that is not susceptible to chemical etching or heat removal) to form a composite waveguide block 600. Then, as Fig. 7E As shown in FIG. 6 , the composite waveguide block 600 can be cut along a plane 603 corresponding to the top surface 13 and the bottom surface 14 of the second waveguide slice 11 to form a composite waveguide block 600 as shown in FIG. Figure 7F The third waveguide slice shown in FIG. Figure 7FAs shown, the mixer block 400 is aligned with the waveguide stack 500 so that the mixer surface or homogenizer 440 appears to be embedded approximately halfway (in the Z direction) relative to the waveguide slice 11. Typically, an optical mixer or homogenizer such as homogenizer 440 corresponds to a symmetrical beam multiplier region having n internal planar beam splitters (where n is a positive integer). Each beam splitter is located inside the resulting LOE 810 and is parallel to the major surface 13 and the major surface 14. Examples of optical mixers or homogenizers such as homogenizer 440 are described in great detail in, for example, U.S. patent application serial number 17 / 420,675 to Ronen et al. (published as publication number US2022 / 0099885). Therefore, optical mixers such as homogenizer 440 are not described in additional detail here. At this stage, the individual slices 11 can be finely polished so that the major surface 13 and the major surface 14 of each waveguide slice 11 are parallel to each other with high precision.

[0051] Next, if Figure 7F As shown in , the waveguide slices 11 can be stacked with alternating placeholders 710 using an adhesive selected from the second group (i.e., an adhesive that is sensitive to chemical etching or heat removal) to form a second waveguide stack 700. The second waveguide stack 700 can then be cut to form an aperture that is coupled into the stack segment 200.

[0052] Figure 7G A top view of the second waveguide stack 700 is shown (i.e., from Figure 7F A view rotated 90 degrees. Figure 7H As shown in FIG. 7 , the first waveguide stack 310 of the stack 700 is cut along a plane 302 to form an aperture surface 301, the plane 302 being perpendicular to the top surface 13 and the bottom surface 14 of the third waveguide slice 11 and intersecting an edge 303 of the first waveguide stack 310 joined to the mixer block 400, to which the coupling-in stack segment 200 can be joined. The coupling-in stack segment 200 is joined to the aperture surface 301 using an adhesive selected from the first group (i.e., an adhesive that is not sensitive to chemical etching or heat removal) to form a third waveguide stack 800.

[0053] As shown in FIG. 7J , the waveguide stack 800 may be cut along a plane 803 corresponding to the bottom surface 14 of the second waveguide slice 11 to form a waveguide slice 810. Portions of the waveguide slice 810 corresponding to the placeholder plate 710 or the sacrificial plate 202 (i.e., any portion bonded using an adhesive selected from the second set of adhesives) may be removed by at least one of chemical etching or heating. The resulting waveguide structure is similar to Figure 2A Corresponding to structure 2a.

[0054] definition

[0055] The following includes definitions of selected terms used herein. The definitions include various examples or forms of components that fall within the scope of the terms and can be used in implementations. The examples are not intended to be limiting. Both singular and plural forms of the terms may be within the definitions.

[0056] An "operable connection" or a connection through which entities are "operably connected" is a connection in which signals, physical communications, or logical communications can be sent or received. Typically, an operable connection includes a physical interface, an electrical interface, or a data interface, but it should be noted that an operable connection may include different combinations of these or other types of connections sufficient to allow operable control. For example, two entities may be operably connected by being able to pass signals to each other directly or through one or more intermediate entities (such as a processor, operating system, logic, software, or other entity). Logical or physical communication channels may be used to create an operable connection.

[0057] To the extent that the terms "include" or "including" are employed in the detailed description or the claims, such terms are intended to be inclusive in a manner similar to the way the term "comprising" is interpreted when used as a transition word in a claim. In addition, to the extent that the term "or" (e.g., A or B) is employed in the specification or the claims, such terms are intended to mean "A or B or both." When applicants intend to indicate "only A or B but not both," then the term "only A or B but not both" will be used. Thus, the use of the term "or" herein is inclusive, rather than exclusive. See Bryan A. Garner, Dictionary of Contemporary Legal Usage 624 (2nd ed. 1995).

[0058] Although example systems, methods, etc. have been described by way of example, and although examples have been described in considerable detail, it is not the intention of the applicant to limit or in any way restrict the scope to such details. Of course, in order to describe the systems, methods, etc. described herein, it is not possible to describe every conceivable combination of components or methods. Additional advantages and modifications will be apparent to those skilled in the art. Therefore, the present invention is not limited to the specific details, representative devices, and illustrative examples shown and described. Therefore, the present application is intended to include changes, modifications, and variations that fall within the scope of the appended claims. In addition, the previous description is not intended to limit the scope of the present invention. On the contrary, the scope of the present invention is determined by the appended claims and their equivalents.

Claims

1. A method for manufacturing a waveguide, the method comprising: Treating the top surface or the bottom surface of the waveguide plate so that the top surface or the bottom surface can partially reflect or diffract; bonding the waveguide plates at the top surface or the bottom surface using an adhesive selected from the first group of adhesives to form a waveguide block having a top surface and a bottom surface; cutting the waveguide block along a plane that is at an acute angle relative to a top surface and a bottom surface of the waveguide block to form a waveguide slice having an internal facet; bonding a first plate to the front surface of the first block to form a second block having a top surface and a bottom surface; cutting the second block to form placeholder slices; as well as alternating and bonding the waveguide slices with the placeholder slices using an adhesive selected from a second group of adhesives to form a waveguide stack, Wherein, the second group of adhesives is composed of adhesives that are more susceptible to chemical etching or heating removal than corresponding adhesives in the first group of adhesives.

2. The method according to claim 1, comprising: Processing the top surface of the coupling plate so that the top surface of the coupling plate can reflect or diffract; bonding the coupling plates together using an adhesive selected from the second group of adhesives to form a coupling stack having a top surface and a bottom surface; as well as The coupling stack is cut along a plane that is at an acute angle relative to the top and bottom surfaces of the coupling stack to form one or more coupling stack segments including a coupling plane segment.

3. The method according to claim 1, comprising: Processing the top surface of the coupling plate so that the top surface of the coupling plate can reflect or diffract; bonding a top surface of the coupling plate to a first surface of a sacrificial plate using an adhesive selected from the first group of adhesives, and bonding a bottom surface of the coupling plate to a second surface of the sacrificial plate using an adhesive selected from the second group of adhesives to form a coupling stack having a top surface and a bottom surface; as well as The coupling stack is cut along a plane that is at an acute angle relative to the top and bottom surfaces of the coupling stack to form one or more coupling stack segments including a coupling plane segment.

4. The method according to claim 2 or claim 3, comprising: The coupling plane segments are bonded to corresponding waveguide slices in the waveguide stack using an adhesive selected from the first group of adhesives to form a waveguide structure.

5. The method according to claim 4, comprising: The waveguide structure is cut along a plane parallel to the top and bottom surfaces of the waveguide structure to form one or more waveguide structure segments.

6. The method according to claim 5, comprising: Portions joined using an adhesive selected from the second group of adhesives are removed from one or more of the waveguide structure segments by at least one of chemical etching or heating.

7. A method for manufacturing a waveguide, the method comprising: producing a waveguide stack in which at least some of the elements are bonded using an adhesive selected from the first group of adhesives; Processing the top surface of the coupling plate so that the top surface of the coupling plate can reflect or diffract; bonding the coupling plates together or to a sacrificial plate using an adhesive selected from the second group of adhesives to form a coupling stack having a top surface and a bottom surface; cutting the coupling stack along a plane that is at an acute angle relative to a top surface and a bottom surface of the coupling stack to form one or more coupling stack segments including a coupling plane segment; bonding the coupling plane segments to corresponding waveguide slices in the waveguide stack using an adhesive selected from the first group of adhesives to form a waveguide structure; wherein the second group of adhesives is comprised of adhesives that are more susceptible to chemical etching or thermal removal than corresponding adhesives in the first group of adhesives; cutting the waveguide structure along planes parallel to the top and bottom surfaces of the waveguide structure to form waveguide structure segments; and Portions joined using an adhesive selected from the second group of adhesives are removed from one or more of the waveguide structure segments by at least one of chemical etching or heating.

8. The method according to claim 7, wherein: Generating a waveguide stack comprises: Treating the top surface or the bottom surface of the waveguide plate so that the top surface or the bottom surface can partially reflect or diffract; bonding the waveguide plate at the top surface or the bottom surface using an adhesive selected from a first group of adhesives to form a first block having a top surface and a bottom surface; cutting the first block along a plane that is at an acute angle relative to a top surface and a bottom surface of the first block to form the waveguide slice having an internal facet; cutting the second block to form spaced slices; and The waveguide slices are alternately and joined with the spacer slices to form the waveguide stack.

9. The method according to claim 8, comprising: The top and bottom surfaces of the waveguide slice are polished, including removing a portion of the first plate that remains adhered to the top surface.

10. A method for manufacturing a waveguide, the method comprising: Processing the top surface or the bottom surface of the first waveguide plate so that the top surface or the bottom surface of the first waveguide plate can partially reflect or diffract; bonding the first waveguide plate at a top surface or a bottom surface using an adhesive selected from a first group of adhesives to form a first waveguide block; cutting the first waveguide block along a first plane at an acute angle relative to the top surface and the bottom surface to form one or more first waveguide slices having internal facets; Processing the top surface or the bottom surface of the second waveguide plate so that the top surface or the bottom surface of the second waveguide plate can partially reflect or diffract; bonding the second waveguide plate at a top surface or a bottom surface using an adhesive selected from the first group of adhesives to form a second waveguide block having a top surface and a bottom surface; cutting the second waveguide block along a third plane at an acute angle relative to the top and bottom surfaces of the second waveguide block to form one or more second waveguide slices having internal facets; bonding the waveguide slices using an adhesive selected from the first group of adhesives to form a waveguide stack; Processing the top surface or the bottom surface of the third waveguide plate so that the top surface or the bottom surface of the third waveguide plate can partially reflect or diffract; bonding the third waveguide plate at a top surface or a bottom surface using an adhesive selected from the first group of adhesives to form a mixer block having a top surface and a bottom surface; bonding at least one of the first waveguide slices to the mixer block, and bonding the mixer block to the waveguide stack to form a composite waveguide block; cutting the composite waveguide block along a plane corresponding to a top surface or a bottom surface of the second waveguide slice to form a third waveguide slice; as well as The third waveguide slices are alternately and bonded with the placeholder using an adhesive selected from a second group of adhesives to form a second waveguide stack, wherein the second group of adhesives is composed of adhesives that are more susceptible to chemical etching or heat removal than corresponding adhesives in the first group of adhesives.

11. The method according to claim 10, comprising: At least one of the first waveguide slices is cut along a plane perpendicular to the top and bottom surfaces of the third waveguide slice and intersecting an edge of at least one of the first waveguide slices joining the mixer block to form an aperture surface.

12. The method according to claim 11, comprising: Processing the top surface of the coupling plate so that the top surface of the coupling plate can reflect or diffract; bonding the top surfaces of the coupling plates together using an adhesive selected from the second group of adhesives to form a coupling stack having a top surface and a bottom surface; as well as The coupling stack is cut along a plane that is at an acute angle relative to the top and bottom surfaces of the coupling stack to form one or more coupling stack segments including a coupling plane segment.

13. The method according to claim 11, comprising: Processing the top surface of the coupling plate so that the top surface of the coupling plate can reflect or diffract; bonding a top surface of the coupling plate to a first surface of a sacrificial plate using an adhesive selected from the first group of adhesives, and bonding a bottom surface of the coupling plate to a second surface of the sacrificial plate using an adhesive selected from the second group of adhesives to form a coupling stack having a top surface and a bottom surface; as well as The coupling stack is cut along a plane that is at an acute angle relative to the top and bottom surfaces of the coupling stack to form one or more coupling stack segments including a coupling plane segment.

14. A method according to claim 12 or claim 13, comprising: bonding an in-coupling stack segment to the aperture surface using an adhesive selected from the first group to form a third waveguide stack; cutting the third waveguide stack along a plane corresponding to a bottom surface of the second waveguide slice to form a fourth waveguide slice; as well as The portions bonded using an adhesive selected from the second group of adhesives are removed by at least one of chemical etching or heating.

15. A method of manufacturing a waveguide for a head mounted display, comprising: bonding a first set of waveguide elements using one or more adhesives that are sensitive to heat or chemical removal and bonding a second set of waveguide elements using one or more adhesives that are not sensitive to heat or chemical removal to form a waveguide stack; cutting the waveguide stack to form a waveguide structure having embedded facets or diffractive elements; as well as Portions corresponding to the first set of waveguide elements are removed using thermal or chemical removal, while portions corresponding to the second set of waveguide elements remain bonded.

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